Development of an operational remote sensing monitoring system for the UNESCO World Heritage tropical forest sites&nbsp(UNESCO-WATCH)

With the increasing amount of new World Heritage sites being inscribed, it has become difficult to monitor all sites in a reliable and operational manner. For instance, only approximately 15% of the 689 World Heritage sites could be examined during the 2008 session of the World Heritage Committee regarding the state of conservation of the sites. The UNESCO and the World Heritage Committee must thus have a methodology to monitor at the long term 100% of the sites in such a way that the World Heritage Committee session could concentrate only on those sites which present particular issues, problems or threat. Similarly, the regular production of thematic maps (forest map, land cover change map…) can improve the local management of the sites.

The overall goal of this project is to develop for UNESCO an operational methodology that, using earth observation from space, can assess the state of conservation for the UNESCO World Heritage tropical forest sites. This will also support the reporting of countries with respect to the “state of conservation” at their tropical forest sites.

The scientific objective is to establish an overall non site specific methodology and processing chain to detect forest and other land cover changes on regular basis.

Method

The research in this project focusses on the use of satellite remote sensing data from optical and SAR sensors in order to perform wall-to-wall monitoring of WH sites. The method includes

an image normalization method using coarser resolution images

temporal image segmentation to build meaningful processing units

unsupervised discrepancy detection to provide change probability maps

thematic interpretation of the discrepancies and

validation of the results. These steps will be included in an automatic processing chain that can use both optical and active sensor images.

This processing chain will take advantage of recent developments in Geographic Object-Based Image Analysis. Indeed, GEOBIA helps to reduce the number and the variability of the entities of interest. Combining image segmentation with a non-parametric statistical discrepancy detection method in space and time, the proposed method is designed to be adaptable to different sites.

Result

In addition to scientific publications, the main output of the UNESCO-WATCH project is a semi-automated processing chain from orthorectified images to land cover change data. The main challenge of this processing chain is to handle the large amount of data and the diversity of image types that are necessary to perform large scale wall-to-wall monitoring in tropical regions.

This processing chain is accompanied by a technological transfer to the UNESCO partner that will run it operationnally for the totality of the Wold Heritage sites containing humid tropical forests.